1. Field of the Invention
The present invention relates to a mobile data-communication system.
This application is based on patent application No. Hei 9-335556 filed in Japan, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Conventional mobile data-communication systems are based on a one-to-one system. An example of the conventional system is disclosed in "PERSONAL DIGITAL CELLULAR TELECOMMUNICATION SYSTEM", the Standards of the ARIB (Association of Radio Industries and Businesses), RCR STD-27F, the third volume, appendix 3-18, April, 1991 (first standardization) to February, 1997 (revision).
The following are problems generated by the above conventional mobile data-communication system:
The first problem is that data communication in connection with multiple lines is impossible. The reason is that only one-to-one data communication is regulated in the system.
The second problem is that when line quality is inferior, real-time data transmission is impossible. The reason is that even with lines having inferior qualities, all data are always transmitted in the regulated system.